Deven

I just past 3200 miles and everything has been going well. On the way to drop the kids to school, and about 10 miles into the drive, the car started to shake/flutter quite aggressively soon after a stop at a red light. With gental accelleration the car would oscillate back and forth (kind of like running out of gas but very rhymically), and the RPM guage would also occilate 200-300rpm back and forth. It was worse in 1st and 2nd gear. Initially it felt like I may have had a flat (but the TPMS did not show this), it also felt like something was stuck to one of the tires, BUT when the clutch was pressed and the car moving, the problem stopped. Similarly when the accelerator was release, the problem also improved.

After stopping the car at school (about 10 minutes) and driving the car to work, the problem was less noticable. Since I was quite concerned, I checked the car about 90 minutes latter and drove around the block (2-3 miles) and the problem is gone.

I am not sure if I should be concerned about this and take it to the dealer or wait and see if it happens again. I have only been using Shell gasoline (91 octane the best I can find) and the tank was 3/4 empty. Has anyone experienced such an issue in the past? Is this something I should worry about? Thanks in advance.

MMD

Sounds like the fuel pump? As long as the check engine light stays off I'd say don't worry too much but get the car in for service check anyway.

OCBen

Check out what happened to Josh here. Must have something to do with dropping off the kids. j/k

https://rennlist.com/forums/997-forum/235679-check-engine-return-to-workshop-she-s-home.html

cvazquez

Did you gas up @ a different gas station, if so, stop going there. Also, could be a faulty gas filter or pump.

ds2k1

Deven, this sounds very much like what happened to my wife's X5 a few months back. I'm not a mechanic, or very mechanically inclined, so I can't remember exactly what the issue was, but it was an electrical problem. Something to do with the electrical system that controlled the throttle. Essentially, when you stepped on the gas, the car would buck back and forth and the engine would rev up and down very erratically. If that's what's happening with your car, you should DEFINITELY get it checked out. This problem actually stranded us on New Year's Eve this year, despite having "fixed" itself on numerous occasions before by simply turning the car off and on.

Le Chef

Have your dealer tech run a diagnostic check. Sounds a bit like a MAF sensor.

doc2s

had the same problem happen to me twice and it disapears on ts own. took the car to the delaer next days but the probelm was gone. delaer ran diagnostics on it and all was normal no logged faults, ignition coils were ok, throttle sneors were ok. not sure what to do.

Stephenkng

Did you try to change gas band after that?

doc2s

i only use mobil or shell 93.had no problem for about 9000 miles.

Deven

Thanks for all the replys. I did fill up with gas this morning after the problem(I used Shell again, but at a different pump). On my way back home this afternoon(22 miles), no issues at all. The check engine light never came on. The only thing out of the 'ordinary' was on Sunday (2 days ago), I had a 'spirited' drive with some fellow rennlisters over 80-90 miles round trip. I did push the RPM towards redline (1st-2nd gear), but never was over 7000, but I was consistently in the 4000-5000 range and frequently was in the 6000 for segments around curves and up and down mountains (the car is just freaking amazing). The engine and oil temps were always 'normal'. The problem sounds similar to what ds2k1 describes, but perhaps not as severe. I could have used another brand of gas today, but Shell has been pretty good. The difference was that I have used different gas stations, all along, and prior to the drive on Sunday I filled at a new station (still Shell) (which should not make a difference?). I certainly will call the dealer and ask them to check the car. I use it as a daily driver and cannot 'afford' to be stranded. Thanks for all the tips/advice.

THPorsche

so what brand of gas do you guys use? I use 76.

997Opus

I only use Chevron premium with Techron. This is the only additive that I feel actually works and helps protect my engine. In fact, my Porsche dealership always puts in a bottle of Techron in her after each oil change/visit for maintenance.

drbf

Exxon 93 or Amoco 93 octane. I did have a problem as described above with water
in my gas tank.

jcf7

In NY and Conn I have no problems finding 93....shell, mobil, or exxon.

Deven

It seems that on the west coast 91 octane is the max. Also they add 10% ethanol April-October and then something called MTBE for the other six months.